Michael Lopp, writing for Rands in Response:
Great design makes learning frictionless. The brilliance of the iPhone and iPad is how little time you spend learning. Designers’ livelihood is based on how quickly and cleverly they can introduce to and teach a user how a particular tool works in a particular universe. In one universe, you sport a handheld Portal gun that cleverly allows you to interrupt physics. In a slightly different universe, you have this tool called a cloning stamp that empowers you to sample and copy any part of a photo.
Awesome article. If you love design, this is an really smart read, illustrating how the goals of game and application designers have so much in common.